Standard Deviation Calculator

Use this free standard deviation calculator to find sample standard deviation, population standard deviation, variance, mean, count, steps, copy, and history.

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Formula steps Examples included Copy results Private history
Sample standard deviation2.1380899353
Mean
5
Variance
4.5714285714
Count
8

Steps

  1. Find the mean: 5.
  2. Find each distance from the mean and square it.
  3. Divide by n - 1 for sample variance.
  4. Take the square root of the variance.

How to use the standard deviation calculator

  1. Enter a list of numbers separated by commas, spaces, or line breaks.
  2. Choose Sample when your values are a sample, or Population when the list is the full group.
  3. Press Calculate standard deviation to see variance, mean, range, and formula steps.
  4. Use examples, recent answers, or copy the result while checking statistics work.

Common uses

Measure how spread out a list of numbers is from its mean.

Compare sample standard deviation with population standard deviation.

Check statistics homework, study data, measurements, and class examples.

Copy the standard deviation, variance, mean, and count for notes.

Examples

Population data 2, 4, 4, 4, 5, 5, 7, 9

Population SD = 2

Sample data 2, 4, 4, 4, 5, 5, 7, 9

Sample SD = 2.1380899353

Small data set 12, 15, 19, 21, 22, 26

Mean = 19.1666666667

Frequently asked questions

Quick answers about formulas, inputs, examples, result copying, and private in-browser history.

What does standard deviation measure?

Standard deviation measures how far data values typically are from the mean. A larger standard deviation means the values are more spread out.

Should I use sample or population standard deviation?

Use sample standard deviation when your data is a sample that estimates a larger population. Use population standard deviation when the data includes the whole group you care about.

Why does sample standard deviation divide by n - 1?

Sample standard deviation divides by n - 1 to correct for estimating population spread from a sample. This is often called Bessel correction.

How many values can I enter?

You can enter up to 1,000 values separated by commas, spaces, semicolons, or new lines.

Can the standard deviation be zero?

Yes. Standard deviation is zero when every value in the data set is exactly the same.

Is my standard deviation history private?

Yes. Recent answers stay only in the current browser tab while you use the page. They are not sent to a server.

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